基于易损性曲线的深埋隧道抗震韧性分析

Seismic Resilience Analysis of Deep-buried Tunnels Based on Fragility Curves

  • 摘要: 深埋隧道抗震性能直接影响城市的韧性水平与灾后的恢复能力。传统抗震分析多侧重于结构强度破坏,而基于易损性曲线的韧性评估方法能够量化隧道在不同地震强度作用下的损伤概率及功能损失,为隧道全寿命周期抗震性能优化设计提供依据。文章以软土地区深埋盾构隧道为研究对象,采用混凝土损伤本构模型模拟隧道衬砌材料,考虑不同地震特性,基于有限元软件建立土体-结构相互作用下的深埋隧道二维动力数值模型;通过增量动力分析方法,研究不同地震强度作用下隧道内力与变形的动态响应规律;在此基础上,以地表峰值加速度为地震动强度指标,以隧道直径变形率和弯矩比为损伤指标,建立深埋隧道抗震概率需求模型,并构建不同地震强度作用下的深埋隧道地震易损性曲线,得到不同损伤状态下隧道的失效概率;进一步结合隧道的功能恢复函数,量化隧道在不同地震动强度作用下的韧性指标,实现深埋隧道的抗震韧性分析。结果表明,随着地震强度的增大,深埋隧道的韧性指标逐渐减小,但仍可保持在Ⅱ级以上水平,表现出较好的抗震韧性。

     

    Abstract: Seismic performance of deep-buried tunnels directly affects the resilience of cities and their post-disaster recovery capability. Traditional seismic analyses mainly focus on structural strength failure, whereas resilience-based evaluation using fragility curves enables quantitative assessment of the damage probability and functional loss of tunnels under different seismic intensities, thereby supporting resilience-oriented design throughout the tunnel life cycle. In this study, a deep-buried shield tunnel in soft ground is adopted as the research object. The concrete damage constitutive model is used to represent the tunnel lining, and a two-dimensional dynamic numerical model considering soil-structure interaction is established using finite element software, incorporating different seismic characteristics. Through incremental dynamic analysis, the dynamic response of tunnel internal forces and deformations under varying seismic intensities is investigated. Based on the peak ground acceleration as the intensity measure and deformation ratio and bending moment ratio as engineering demand parameters, the seismic probabilistic demand model of the deep-buried tunnel is constructed. Subsequently, fragility curves corresponding to different seismic intensities are developed to obtain the failure probabilities under various damage states. Furthermore, by incorporating the functional recovery function of the tunnel, the seismic resilience index is quantified for different seismic hazard levels, enabling the seismic resilience assessment of deep-buried tunnels. Results indicate that the resilience index decreases with increasing seismic intensity; however, the deep-buried tunnel can still maintain a Level II or above resilience rating, demonstrating favorable seismic resilience.

     

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